Alkali Earth-Transition Metal Composite Catalyst for Reverse Shift Reaction
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Solution Overview
Problem
Existing catalysts for reverse shift reactions face challenges in operating at high temperatures and suppressing methanation reactions, which reduces the concentration of carbon monoxide in synthesis gas produced.
Innovation Solution
A composite oxide catalyst containing alkali earth metals like Ca, Sr, and Ba, combined with transition metals such as Ti and Zr, is used to promote the reverse shift reaction at temperatures above 700°C, effectively suppressing methanation and enhancing the production of synthesis gas with high carbon monoxide and hydrogen content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If common shift reaction catalysts are used for reverse shift reaction at high temperature (600°C or higher), then the equilibrium composition of synthesis gas is improved, but the catalyst activity deteriorates due to temperature mismatch
Solution Approach 1:
The patent changes the chemical composition parameters of the catalyst by incorporating specific alkali earth metals (Ca, Sr, Ba) and transition metals (Ti, Zr) in defined ratios. This compositional modification enables the catalyst to maintain high activity at elevated temperatures (600-1000°C) required for optimal reverse shift reaction equilibrium, resolving the temperature-mismatch problem between conventional shift catalysts and reverse shift reaction conditions
Solution Approach 2:
The patent creates a composite catalyst material combining multiple metal oxides (alkali earth metal oxides + transition metal oxides) with synergistic effects. This composite structure provides both the thermal stability needed for high-temperature operation and the catalytic activity required for efficient reverse shift reaction, simultaneously addressing both the equilibrium composition and catalyst activity requirements
2Productivity
If pressurized conditions are applied to reverse shift reaction, then reaction efficiency is improved, but methanation reaction occurs which reduces carbon monoxide concentration
Solution Approach 1:
The patent creates catalysts with different local compositions and properties by controlling the ratio of alkali earth metal to transition metal components. Specific local compositions (e.g., higher transition metal content) are designed to suppress methanation activity while maintaining reverse shift reaction efficiency, allowing selective promotion of desired reaction pathways under pressurized conditions
Solution Approach 2:
The patent converts the potential harmful effect of pressurized conditions (which promote methanation) into a benefit by designing a catalyst that is specifically optimized for high-pressure operation. The catalyst structure enables the system to operate efficiently under pressure while the catalyst's selective activity suppresses unwanted methanation, turning a challenging condition into an advantageous operating regime
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The catalyst efficiently promotes the reverse shift reaction at high temperatures, reducing methane generation and increasing the ratio of carbon monoxide and hydrogen in the synthesis gas, while maintaining high catalytic activity and preventing methanation side reactions.
Implementation Method 1
a catalyst for a reverse shift reaction, which is active for a reaction for generating carbon monoxide and water vapor from carbon dioxide and hydrogen
Data Source
AI summary
There are provided a catalyst for reverse shift reaction which has excellent durability at a high temperature, can suppress generation of a methanation reaction, and can efficiently generate a reverse shift reaction to produce a synthesis gas including carbon monoxide and unreacted hydrogen with a reduced methane content, and a method for producing a synthesis gas using the catalyst for reverse shift reaction. The composition of the catalyst for the reverse shift reaction includes a composite oxide containing at least one alkali earth metal selected from the group consisting of Ca, Sr and Ba and at least one transition metal selected from the group consisting of Ti and Zr. A raw material gas containing carbon dioxide and hydrogen is contacted with the catalyst for reverse shift reaction at a temperature of 700° C. or higher.